#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>

void reverseString(char* s, int sSize) {
	int left = 0;
	int right = sSize - 2;
	while (left <= right)
	{
		char tmp = s[left];
		s[left] = s[right];
		s[right] = tmp;
		left++;
		right--;
	}
}

int main()
{
	char str[] = "abcd";
	int sSize = sizeof(str) / sizeof(str[0])-1;
	reverseString(str, sSize);
	printf("%s\n", str);
	return 0;
}